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Unchamfered Thin Hex Nut Dimensions (ISO 4036, M1.6 to M10)

Guide · Updated October 28, 2026

ISO 4036 covers unchamfered hexagon thin nuts, style 0, product grade B, with coarse thread from M1.6 to M10. Values come from the ISO 4036:2012 preview table and agree with the Welfast ISO 4036 table on every value. The globalfastener DIN EN ISO 4036 table also agrees on every value except M10 s min, which it lists as 16.57 mm, larger than s max, so that is a typo; we use 15.57 mm from ISO and Welfast. Not shown: fine pitch variants (not part of the standard). Check the current edition or your supplier for critical work.

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Step by step

Confirm the size range: ISO 4036 only covers M1.6 to M10 coarse thread. For M3 to M36 chamfered jam nuts use ISO 4035.
Pick the wrench: s max is the wrench: M3 5.5 mm, M4 7 mm, M5 8 mm, M6 10 mm, M8 13 mm, M10 16 mm.
Check the height: m max is about half a full nut: M6 3.20 mm, M8 4.00 mm, M10 5.00 mm.
Know it is grade B: Product grade B means looser tolerances than grade A nuts. Fine for light duty and locking, not for load.
Expect no chamfer: Both faces are flat with sharp hex corners, so there is no bearing face and no preferred side.
Use it as a jam nut: Tighten it against a full nut or a part to lock position. Do not count on it to carry full bolt load.

ISO 4036 unchamfered thin hex nut dimensions (mm)

Columns: thread size and pitch, width across flats s max and min (s max is the wrench size), width across corners e min, nut height m max and min.

Size | s max | s min | e min | m max | m min
M1.6 x 0.35 | 3.20 | 2.90 | 3.28 | 1.00 | 0.75
M2 x 0.4 | 4.00 | 3.70 | 4.18 | 1.20 | 0.95
M2.5 x 0.45 | 5.00 | 4.70 | 5.31 | 1.60 | 1.35
M3 x 0.5 | 5.50 | 5.20 | 5.88 | 1.80 | 1.55
M3.5 x 0.6 | 6.00 | 5.70 | 6.44 | 2.00 | 1.75
M4 x 0.7 | 7.00 | 6.64 | 7.50 | 2.20 | 1.95
M5 x 0.8 | 8.00 | 7.64 | 8.63 | 2.70 | 2.45
M6 x 1 | 10.00 | 9.64 | 10.89 | 3.20 | 2.90
M8 x 1.25 | 13.00 | 12.57 | 14.20 | 4.00 | 3.70
M10 x 1.5 | 16.00 | 15.57 | 17.59 | 5.00 | 4.70

Worked example: screw length for an M4 thin nut

Grip 6 mm, full nut ISO 4032 M4 m max 3.2 mm, ISO 4036 thin nut m max 2.20 mm, plus 2 threads at 0.7 mm = 1.4 mm. Total 12.8 mm, so an M4 x 14 screw works.

Common problems

Mixing DIN 439 stock with a different hex size into ISO bins.
Using a thin nut as the only nut on a loaded joint: it can strip.
Sharp unchamfered corners can mark soft parts; add a washer.

ISO 4035 vs ISO 4036 side by side (M3 to M10)

Both are thin hex nuts. ISO 4035 is chamfered, product grade A up to M16 (B above), and runs M3 to M36. ISO 4036 is unchamfered (style 0), grade B only, and stops at M10. Where sizes overlap, wrench size s max and height m are the same; the wider grade B tolerance shows up as a lower s min and e min on ISO 4036. Values below are copied from the two charts on this site (mm).

Size | s max | s min 4035 / 4036 | e min 4035 / 4036 | m max (both)
M3 | 5.50 | 5.32 / 5.20 | 6.01 / 5.88 | 1.80
M4 | 7.00 | 6.78 / 6.64 | 7.66 / 7.50 | 2.20
M5 | 8.00 | 7.78 / 7.64 | 8.79 / 8.63 | 2.70
M6 | 10.00 | 9.78 / 9.64 | 11.05 / 10.89 | 3.20
M8 | 13.00 | 12.73 / 12.57 | 14.38 / 14.20 | 4.00
M10 | 16.00 | 15.73 / 15.57 | 17.77 / 17.59 | 5.00

Which to pick: same wrench and same stack height, so they swap in a fixture. Choose ISO 4035 when you need a property class (04, 05), sizes above M10, or a chamfer that will not mark the part. Choose ISO 4036 for small instrument and adjuster lock nuts where cost matters and below M3 (M1.6 to M2.5 exist only in ISO 4036). Inspect s with a caliper against the lower s min for the grade you bought.

Sources: ISO 4035 chart and ISO 4036 chart.

FAQ

Can an ISO 4035 nut replace an ISO 4036 nut?

Yes from M3 to M10: same wrench size and height, tighter grade A tolerances, and a chamfer. Below M3 there is no ISO 4035 size, so stay with ISO 4036 for M1.6 to M2.5.

What is the difference between ISO 4036 and ISO 4035?

ISO 4035 thin nuts are chamfered, grade A/B, and run M3 to M36. ISO 4036 are unchamfered, grade B, and only M1.6 to M10. Heights match where sizes overlap.

Is ISO 4036 the same as DIN 439 A?

Close. DIN 439 form A was the unchamfered thin nut. Some DIN sizes used different hex widths (M10 17 mm), so check the wrench.

What wrench fits an M5 ISO 4036 nut?

8 mm.

Why buy unchamfered thin nuts?

They are cheap to make and fine for small instrument, electronics and adjustment work where a thin locking nut is all you need.

What material are ISO 4036 nuts?

Steel with min hardness 110 HV30, or non-ferrous metals per ISO 8839. There is no property class like 8 or 10.

Why is M3.5 in parentheses?

ISO marks M3.5 as non-preferred. Avoid it if you can.

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